Diesel engine vehicles are the vehicles of choice for persons towing large loads. The power to pull a load, sometimes two or three times the gross vehicle weight (GVW) of the diesel engine, plus the fuel mileage delivered by diesel engines with such loads, is significantly greater than that possible in similar size gasoline engines.
However, in mountainous or hilly regions or any place where significant grades in roads are found, gasoline engine vehicles hauling loads have an advantage in stopping power over diesel engine vehicles. This advantage is inherent in the design of the gasoline engine, as the gasoline engine is designed with a carburetor that includes a throttle valve, often referred to as a butterfly. When the accelerator, or throttle, is not engaged, as when braking, the butterfly closes off the air intake of the engine forming a compressor effect that assists the vehicle in braking. This is not possible in diesel engines as diesel engines have no analogous structure. When the accelerator of the diesel engine is released, the engine idles with no (or insignificant) change in internal air pressure. No compression is developed and the brakes of the vehicle are given the entire task of stopping the vehicle. When the vehicle has a light load or is on flat land, the brakes are generally adequate on their own, but in the situations described above, generally the brakes are over-exerted and wear out sooner or dangerously overheat.
Valley Fuel Injection, Ltd. of Abbotsford, B.C., Canada, has developed a braking device for use in diesel engine exhaust pipes that purports to produce an effect that is similar to the butterfly of a gasoline engine. Basically, the "BD Engine Brake" causes a compression-type braking effect by causing a valve to close within the exhaust system of a diesel vehicle. The BD brake valve is simply a piece of metal having a shape that fills the cross-section of the exhaust pipe when it is engaged. The BD brake valve can be either open, so that it allows all of the exhaust gases to escape from the engine, as when accelerating, or closed so that it blocks nearly all of the exhaust from the engine when braking. The results are that when the valve is closed a considerable compression force is developed that assists in the braking of the vehicle. When the valve is open, all of the gases escape and no assistance is given to the braking force of the vehicle. When the valve is closed, pressure builds in the exhaust pipe, between the valve and the engine, such that the engine may be damaged or choked and caused to cease operations. To alleviate this, the valve must be periodically opened. However, as noted above, the opening of the valve causes all of the exhaust gases to escape and stops the brake assistance abilities of the BD brake. When the valve is subsequently closed again, pressure must once again build in the exhaust system. The results of using the BD brake are that the user receives peaks and valleys of brake assistance with no continuity to the braking force. Further, there is a danger in using the BD brake in that without due diligence, the brake can cause damage to the engine.
Other manufacturers of similar type brakes have attempted to alleviate the danger of engine damage and choking somewhat by allowing the continuous release of some exhaust gas even when the brake is engaged. This has been done, for example, by perforating the valve so that some exhaust gas escapes all of the time or by causing the valve to not seal completely when closed, for the same effect. Unfortunately, this is a very inaccurate means of regulating pressure and as a result the full effectiveness of the compression braking is not achieved. Further, this means of releasing gases may, due to its inaccuracies, still cause damage to the engine or cause the engine to choke and stall.
I have invented a vehicle engine brake that places an engine in a compression braking mode and can be used in either the exhaust system or in the air-intake system of a vehicle, while allowing excess pressure to be relieved, through regulable means. The present invention provides excellent brake assistance by creating pressure on the engine that causes a compression braking effect and continuity of brake assistance without damaging or choking the engine. Further, as the engine is placed in a compression mode, by the activation of the present device, the engine is allowed to run in such a way that provides a means to bring a diesel engine to operating temperatures and warm up the passenger compartment of a vehicle (on cold days). Previously, diesel engines and passenger compartments had to be started and warmed up by staying in the cold cab while maintaining pressure on the accelerator pedal.
It is therefore an object of the present invention to provide a vehicle engine brake that will assist in the stopping of the vehicle without choking the engine into a stall.
It is a further object of the present invention to provide a means to warm up a diesel engine and the passenger compartment of a diesel vehicle prior to driving the vehicle.
Other objects and advantages of the present invention will become apparent as the description proceeds.